Penicillin

Diagram illustrating high potency of penicillin when first purified.

The mass production of penicillin saved a large number of lives during the Second World War. From early 1944, British and American armed forces used the medicine widely, both to cure infected wounds and to treat the sexually transmitted infections gonorrhoea and syphilis. Immediately after the war in Europe ended in May 1945 there was a threat of a widespread syphilis epidemic. Many among the millions of lonely male soldiers met and sometimes sexually exploited starving women. Penicillin averted the epidemic because a few doses would generally lead to a total cure.

In the postwar years, as penicillin became widely available it greatly reduced the health risks of sexual intercourse and sustained changes in moral values. It was also so widely used to treat young children and babies suffering from earache and other infections that most people had received a dose by the age of two. The disease of pneumonia, which was once frequently fatal or required weeks of hospital care, could generally be cured in a few days.

However, the widespread use of penicillin also bred resistant bacteria. Even in the 1950s there was an epidemic of virulent salmonella. And when chemists developed a new kind of penicillin, called methicillin, which could beat the resistant bacteria, a new strain of methicillin-resistant Staphylococcus aureus (MRSA) quickly emerged. MRSA was first observed in the 1960s, but only became a major threat in the 1990s.